Wax Begonias and Wasps

Giant Whitefly

• The giant whitefly (Aleurodicus dugesii) measures up to 3/16 inch in length and leaves behind a collection of white wax as it infests the wax begonia. The pest sucks away the sap of the plant, causing a discoloration of leaves and defoliation of the begonia. It also deposits honeydew -- waste -- that results in the development of a black, sooty mold on the plant. Several species of parasitic wasps are drawn to the begonia in order to feed on the giant whitefly.

Wasps

• A parasitic wasp with red eyes called Entedononecremnus krauteri helps minimize damage to a wax begonia by attacking the giant whitefly. The wasp can be found on the upper surface of leaves where the wasp punctures the surface of the leaves and then forces its own eggs into the bodies of giant whiteflie larvae that feed on the under surface of the foliage. Upon hatching, the larvae of the wasp feed on the larvae of the giant whitefly.

Effectiveness

• Two other species of parasitic wasps, Encarsiella noyesii and Idioporus affinis are tiny, sting-less wasps that attack the larvae of the giant whitefly in the same manner as Entedononecremnus krauteri. When the larvae of these wasps pupate -- transform into adults -- they leave behind a yellow or clear casing. The wasps normally do not completely eradicate the giant whitefly, but they reduce the numbers sufficiently and effectively minimize extensive damage to a wax begonia.

Other Predators

• While wax begonias and wasps enjoy a mutually beneficial relationship -- the begonia attracts giant whiteflies and the wasps eat them -- other insects are also natural, native predators of the whitefly and can be discovered on the begonia. These include green lacewings, lady beetle adults and larvae, and syrphid fly larvae. However, these insects typically do not provide sufficient biological control of the whitefly. The Asian lady beetle has been introduced by man into the wild as an additional control measure against the giant whitefly.